Numerous methods and apparatus are involved in an ever expanding field, if not science of tillage, the preparation of the soil for seed planting purposes. Today, farmers use and experiment with ridge-tilling, no-tilling, and now are beginning to work with conservation tillage farm equipment and methods. It is the latter to which this invention is directed.
Historically, farmers have relied upon conventional or "deep" tilling to prepare their fields for planting; utilizing a moldboard plow, chisel plow or other cultivating implement which is dragged over the fields after harvest of a prior crop to break up the soil to a substantial depth, to cut and bury the residue of the harvest, and to bring deep soil up to the surface. Several passes of additional implements are required over the same soil prior to planting to facilitate same. Recently the concept of conservation tillage has emerged utilizing the planter as a primary implement to support blade assemblies used to open a furrow of predetermined depth, to deposit seeds within the furrow, and then to close the furrow over the seeds, all in a single or one-pass.
Conservation or no-till planting appeared to reduce the number of tillage trips over the same field; however, the problem of dealing with the residual mulch has been left somewhat unsolved. Residual mulch is that residue of live and dead vegetation and plant stubble left in place by this type planting after harvest. There are benefits such as aiding in the control of erosion, and of fertilization through decomposition; along with disadvantages such as retarding evaporation to leave soil at unacceptably high levels of moisture content. Additional problems of fertilizer application and timing relative to the seedbed preparation increased the considerations of management as to the more contemporary conservation planting.
Reference is made to our prior invention showing a pair of mirrored coulters in U.S. Pat. No. 4,987,841. This arrangement provided an important advance in this field of conservation tillage, however the instant disclosure shows advantages thereover.